It's not only about poor network connection but also poor CPU / RAM, having a website visually lag / taking multiple frames to render is not a great experience

It's not only about poor network connection but also poor CPU / RAM, having a website visually lag / taking multiple frames to render is not a great experience and having a top of the line desktop can make you easily not aware of those issue. There is something very pleasing about everything running smoothly without any hiccups.